The background description provided herein is for the purpose of generally presenting the context of the disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art or suggestions of the prior art, by inclusion in this section.
Materials may be processed using different techniques depending on the type of material, desired end product, quantity of material, energy constraints, interim control constraints, cost constraints, and the like. For example, for biologic material, and in particular, food material, processing may comprise causing food material to be heated using RF energy. While frozen food material may be placed in an area of higher temperature (e.g., from freezer to refrigerator) to passively heat over time, such process may require too long a time period, the end product may be non-uniform, and/or the end product have other undesirable characteristics.
Conversely, frozen food material may be actively heated using, for example, radio frequency (RF) heating techniques. An example RF heating technique may comprise heating the food material at high frequencies, such as frequencies of 13.56 MegaHertz (MHz) to 40.68 MHz. Using such high frequencies, however, may result in lack of uniformity in the heating due to low penetration depth of high frequency radiation. Another example RF heating technique may be implemented using large vacuum tube systems operating at 27 MHz. In such systems, the vacuum tubes may comprise a free running oscillator having a frequency range which may deviate from 27 MHz and may also deviate from Federal Communications Commission (FCC) frequency requirements. Performance characteristics (e.g., power characteristics) of vacuum tubes also tend to degrade as soon as they are put into operation, with vacuum tube lifespans lasting on average a mere two years. Such vacuum tube systems may also operate at several thousand volts, which raise safety concern for nearby personnel, especially since these systems operate in an environment where water or moisture may be present. In other example RF heating techniques, the direct current (DC) to RF power efficiency may be 50% or less.
Accordingly, processing techniques which address one or more of personnel safety concerns, uniformity in the state of the end product, power efficiency, processing control, compact system size, lower energy requirements, system robustness, lower cost, system adjustability, and/or the like may be beneficial.